Apparatus and process for producing mineral fibers



April 25, 1961 B. A. GRAYBEAL APPARATUS AND PROCESS FOR PRODUCING MINERAL FIBERS 3 Sheets-Sheet 1 Filed Dec. 6, 1957 BRUCE A. GRA YBEA L INVENTOR rfiah FIG. I.

ATTORNEYS APP-H 1961 B. A. GRAYBEAL 2,980,953

APPARATUS AND PROCESS FOR PRODUCING MINERAL FIBERS Filed Dec. 6, 1957 5 Sheets-Sheet 2 ATTORNEYS BERS A ril 25, 1961 B. A. GRAYBEAL APPARATUS AND PROCESS FOR PRODUCING MINERAL FI Filed Dec. 6, 1957 3 Sheets-Sheet 3 INVENTOR rgewa a E w m A. x D a ATTORNEYS APPARATUS AND PROCESS FOR PRODUCING MINERAL FIBERS Bruce A. Graybeal, Box 217, Sussex Turnpike, RD. 2,

Dover NJ.

Filed Dec. 6, 1957, Ser. No. 701,260

6 Claims. (Cl. 18-25) This invention relates to improved apparatus and process for producing mineral fibers from silicious raw materials and the like.

The use of steam under pressure has been and still is one of the principal means used to fiberize molten slaglike material to form slag wool. One of the best known systems of fiberization includes a steam V-jet wherein the molten slag stream is contacted on two sides by the V jet of steam, thereby greatly increasing the steam contact on the molten material so as to enhance and speed up the fiberization. In other instances, elficiency of operation has been increased by dividing the parent stream of molten material into a plurality of smaller streams in order that the steam can more readily con tact and act on the molten streams to produce fibers.

This invention embodies the teaching of both of the above, namely, the dividing of the steam jet and the dividing or splitting of the molten material into fine particles.

In view of this, it is an object of this invention to provide a novel method and apparatus for distributing molten slag-like material in fine form and acting thereon with divided blasts of steam under pressure.

It is another and specific object to provide a rotary distributing means for dispersing the molten material in fine particle form and then further subdividing and fiberizing the particles by means of steam blasts from above and below the discharged particles.

it is a further object to provide apparatus and method for transforming the available potential energy of steam under pressure into kinetic energy and utilizing this kinetic energy to attenuate molten slag to form fibers.

ltis a still further object to use the energy of the steam to augment the momentum of unfiberized shot particles developed by the distributing means to etfect a separation of the shot particles from the fibers.

It is also an object to providea novel fiben'zing apparatus for molten slag-like material which is easy, safe and economical to operate, and yet one which produces high quality fibers.

The invention will appear more clearly from the following detailed description when taken in connection with the accompanying drawings, showing by way of example, a preferred embodiment of this invention, and wherein:

Fig. 1 is a side elevational view, partly in section, showing the general arrangement of the apparatus of this invention;

Fig. 2 is an enlarged and generally vertical sectional view taken along line 22 of Fig. l and showing further etails of the apparatus of this invention;

ice

Fig. 3 is a top plan view along line 3-3 of Fig. 2 showing the face of the distributing rotor;

Fig. 4 is a vertical sectional view taken along line 4--4 of Fig. 3 and showing the details of the distributing rotor and steam projecting rings, and

Fig. 5 is a vertical section taken along line 55 of Fig. 2.

In general the apparatus of this invention comprises a fiber collection chamber 10 formed by a generally circularly shaped upright wall 12 situated on a suitable foundation 14 thus providing an open top. A conventional endless belt type conveyor assembly 16 is mounted in the lower portion of the chamber 10 so that the conveyor will catch the fibers produced in the upper portion of the chamber and carry them out of the chamber 10. An annular water-cooled shot deflector 18 having a shape generally conforming to that of the wall 12 is mounted adjacent to and spaced from the upper edge of the wall 12. A cupola 20 is positioned above the upper end of the chamber l0'and so that molten slag-like material may be fed downwardly onto a molten material dispersing assembly 22 positioned therebeneath. This assembly is mounted on a horizontal supporting beam 24 which is in turn secured to a vertical post 26 located outside the chamber 10.

-More particularly, as illustrated in Figs. 1 and 2 the fiber making and collecting chamber 10 is formed by a generally circularly shaped vertical wall 12 mounted on a foundation 14 of suitable refractory material. The back portion 13 of the wall 12 has an air inlet 26 formed in its lower portion to feed air into the bottom of chamber 10 where thefibers are deposited on a conveyor assembly 16, comprising a conventional perforated or other suitable endless belt appropriately carried on rolls at least one of which is powered. The conveyor is so positioned that its upper surface, which receives the fibers moves in the direction indicated in Fig. l to carry the fibers from the chamber 10. The forward portion 15 of wall 12 has openings which allow the conveyor belt to pass therethrough. A vertically reciprocable sealing roll 17 makes it possible to vary the size of the opening through which the fiber layer passes.

A hollow annular, water-cooled shot deflector 18 of generally rectangular cross-section is so formed that it will substantially conform to the shape of the upper end of the wall 12. Water is circulated through the hollow portion of the shot deflector 13 by means of conduits 28 and 30. As indicated, the shot deflector 18 is mounted above and spaced outwardly from the upper edge of wall 12 for purposes which will appear. A circular plate member 32 is centrally positioned in the upper end of the chamber 10 level with the upper edge of the shot deflector 18. This plate has a circular opening 34 centrally disposed therein. Circular air deflectors 36 and 38 having confronting convex faces are respectively secured to the outer edge of the plate 32' and the upper inner edge portion of shot deflector 18, thus forming a somewhat restricted air passageway 40.

A blast furnace type cupola 20 is positioned above the open end of the chamber It so that the breast 42 of the cupola may discharge molten, slag-like material through opening 34 in plate 32.

The molten particle dispersing assembly 22 (Fig. 2) comprises an upper steam ring 44 and a similarly shaped lower steam ring 46 spaced slightly below upper ring 44. As best shown in Fig. 4, the upper ring 44 is generally rectangular in cross section and has an annular opening 48 sloping downwardly and outwardly from the bottom of the hollow portion 50 and emerging in the lower face 52 of the ring 44. A hollow protective shield 54 extends around the lower portion of the inside face of the upper ring 44 and a suitable coolant such as water is circulated through the passageway 56 within the shield. The lower and opposed ring 46, which is of the same general size and shape as the upper ring 44, has an annular opening 58 connecting the upper part of the hollow portion 60 with the outside. his opening 58 slopes upwardly and outwardly from the hollow portion 69 emerging in upper face 62 of the ring 46. The confronting faces 52 and 62 of the upper and lower rings are spaced apart an amount such that the paths of the fluids discharged from their discharge openings will intersect each other immediately adjacent the confronting faces 52 and 62.

Steam is fed to the hollow portion 50 of upper ring 44 by means of conduit 76 which is rotatably mounted at 80 so that a lever 82 appropriately secured thereto may be operated to swing the upper ring upward for reasons to be discussed later. A slotted bracket 84 is secured to the upper ring 44 and arranged so that the slotted portion fits over a pin 86 on plate 32 to guide the upward excursion of upper ring 44. The lower ring 46 is supported by a steam conduit 88 which feeds steam to this ring. The conduit 88 is supported by the horizontal beam 24, which extends through hole 90 in side wall 12 and is in turn supported by vertical post 26.

A distributing rotor 64 (Fig. 4) is so positioned that its cup-shaped portion 66 is concentrically disposed with respect to the steam rings and rotates within the lower steam ring 46. It will be noted that the outer wall 68 of this cup-shaped portion 66 is spaced only a slight distance from the inner face of the ring 46 and that the upper edge portion 70 of the cup-shaped portion 66 is slightly above the adjacent face 72 of the steam ring 46. The cup-shaped portion 66 has a concave upper face 74 and is hollow so that coolant may be fed therethrough. A hollow distributing rotor shaft 92 is suitably secured to the shaft of an electric motor 94 which is supported by the horizontal beam 24. The shaft of the electric motor is hollow and is connected to a water conduit 96 carried by beam 24. Water under pressure is fed through the conduit and the hollow shaft 92 into the hollow portion of the rotor 66 for cooling purposes. Power for the electric motor is supplied through an electrical cable 98 suitably mounted on beam 24 (Fig.

As indicated in Fig. 5, beam 24 is an I-type beam and has a plurality of longitudinally spaced roller assemblies mounted along its length. Each roller assembly comprises three sets of rollers 100 mounted on the beam to engage the inner surface of a cylinder 102 so that said cylinder may rotate therearound. Referring to Fig. 2, the cylinder 102 enters chamber through an opening 90 in wall 12. The cylinder 102 is rotated by means of a pulley 104 afflxed to the outer end of the cylinder, which pulley carries a belt 106 fitting around another pulley 103 secured to the shaft of motor 110. In order to provide a seal around the opening 90, the cylinder 102 is provided with a disk 112 which is positioned adjacent the inner face of the wall 12 and is surrounded by an inwardly extending annular flange 114.

A protective shield 116 is secured to the wall 12 above pulley 104 to protect the pulley and motor 110 from falling shot produced in the fiber making process.

As illustrated in Figs. 1 and 2, a slag flume 118 is swingably mounted by means of U-shaped bracket 120 on the cupola 20 adjacent the cupola breast 42 so that the end of the flume may be swung to interrupt the stream of molten slag-like material dispersed from the cupola and. to cut off flow to the distributing rotor 66;

In operation, silicious raw materials mixed with suitable corrective ingredients well-known in this field, and coke as fuel are charged into the blast furnace type cupola 20 for melting. The molten slag-like material upon being heated to approximately 2700 F.3000 P. will flow freely from the cupola breast 42 in a fluid stream and fall by gravity into the concave face 74 of the distributing rotor 64, which is rapidly rotating at a speed of from 3,000 to 8,000 r.p.m. As indicated in Fig. 3, the turning rotor causes the molten slag-like material to be distributed uniformly around the upper peripheral face 70 of the cup portion 66 of the rotor and discharged tangentially in a substantially horizontal plane in the form of fine, molten slag-like particles between the confronting faces of the upper and lower rings 44 and 46, respectively. These molten particles move directly into an annular turbulent mass of expanding steam produced by converging steam blasts discharged from annular openings 48 and 58 in the upper and lower rings. This steam is under pressure so that the expansion "of the steam plus the converging of the two blasts produces a turbulence which further disperses the molten particles and also serves to cool them to a viscous state wherein fiberization takes place as the steam proceeds outwardly away from the 'two steam rings.

The lower steam ring 46 is stationary while the upper steam ring 44 is mounted on steam conduit 76 which is pivotally connected to lever 82 at point 80. It becomes necessary to raise the upper steam ring 44 only when a particle of coke or unmelted slag coming from the cupola breast is too large to pass between the upper and lower steam rings.

Occasional splattering of slag coming from the cupola breast 42 or careless positioning of the molten slag stream 120 in the concave face of the distributing rotor 64 makes it advisable to protect the delicate and expensive inner wall of the steam ring 44 with a shield 54 made of ab rasion resistant metal alloy. The shield 54 is cooled by water forced through the hollow portion 56 of the shield by suitable means.

The fiberization is completed within a few inches from the point of convergence of the two steam blasts. It is important that the fine fibers be cooled as soon as they are formed to prevent crystallization. The expansion of the steam utilized in this invention takes place radially outward in addition to the widening of the annular mass of steam in the up and down directions. This greatly aids in the rapid cooling of the fibers to produce a more vitreous fiber which is not as friable or dusty as hitherto obtained.

In addition to the desirable vitrifying influence, the

rapidly expanding steam also serves to facilitate fiber collection and shot separation. The fine long fibers have low momentum because of their light weight; consequently they merely attain the velocity of the gases in which they are suspended. Thus the fibers are freely carried in the current of water vapor and air entering the chamber 10 through air inlet 40. It has been observed that air admitted at the rate of 2400 feet per minute through passageway 40 is adequate to prevent the fibers 'from plastering the inside wall of chamber 10.

Inherent in all rock wool manufacturing processes is The shot is principally in the form of beads which are formed when the molten slag cools too much before it is blasted by the steam. The amount of shot produced is to some extent a measure of the efiiciency of the fiberizing apparatus. The

fineness of fiber is also closely related to the amount of shot produced, the finer the fiber, the less shot that will be formed with it.

Even in the mos efficient systems some shot will be formed and it is desirable that such shot be separated from the fiber. As indicated in Figs. 1 and 2, the shot particles 126 which have considerable mass are not deflected by the currents of air brought in through passageway 40. From the converging steam blasts the shot particles receive sufficient impetus to carry them directly through the fiber mass so that they will strike the inner face of the shot deflector 18 and be'deflected downwardly away from and outside of the .chamber A trough 128 extends beneath a portion of they shot deflector 18 generally coextensive with the forward portion of wall 12 to catch the shot striking this portion of the deflector to prevent them from falling on the conveyor carrying the fibers from chamber 10. The shot particles are still in somewhat of a plastic state when they strike the deflector 18 and in this state they will stick thereto. However, as soon as the surface of the shot deflector is cooled by the water forced through the hollow portion 19, the particles will fall off the surface and can then be conveniently removed in any suitable manner.

Again referring to Figs. 3 and.4, the molten slag-like material, which flows from the breast 42 of the cupola and drops into the concave face 74 of the distributing rotor 64, takes a path on the concave face 74 as depicted by the arrows in Fig. 3. As indicated, the molten mate rial progresses in a somewhat spiral path to the upper edge 70 of the concave face and is tangentially discharged therefrom. The true tangential angle is indicated by the shot particles 126 which are not appreciably affected by the converging steam blasts above and below the dispersed particle layer. The molten particles of smaller than shot size are diverted a small amount by the steam blasts and at the end of the fiberization take a course as indicated by the arrows 128. The angle A between the tangential direction in which the small molten particles are initially directed and that of the fibers is the resultant of the tangential direction of the small particles and the radial steam blasts from above and below the particles.

The expanded high-velocity steam loses its momentum rapidly upon leaving its discharge point due to turbulence, eddy currents, and the retarding effect of the air being brought in through the annular passage 40. Therefore, it is important that the exit of the steam blast be placed as close as possible to the molten particles as they are dispersed from the distributing rotor 64 in order to obtain the maximum impetus from the steam. The protective water-cooled shield 54 on the upper steam ring 44 makes it possible for the upper and lower rings 44 and 46 to be placed as close as 7 of an inch on either side of the dispersed layer of molten particles.

The close proximity of the steam blasts to the layer of molten particles also makes possible the use of lower steam pressure. Apart from the advantages of economy, the lower pressure steam is conducive to the formation of longer fibers.

While the preferred form of this invention has been fully disclosed, it is to be understood that various changes may be made in the mode of operation and in the con struction and arrangement of parts that will obtain equivalent results without departing from the invention as claimed.

Having thus described my invention, what I claim as novel and desire to secure by Letters Patent of the United States is:

1. A process for making mineral wool fibers from moltenlslag-like material which comprises introducing a' stream of liquefied slag-like material onto the concave upper face of a distributing rotor turning about a substantially vertical axis, tangentially discharging a layer of fine molten slag-like particles from the outer edge of the concave face portion of the distributing rotor in a.

horizontal plane, and concurrently directing outwardly converging steam blasts onto the discharging layer of molten slag-like particles immediately adjacent the outer periphery of the distributing rotor to cool and fiberize the particles of the molten layer.

2. A process for making mineral wool fibers from molten slag-like material which comprises introducing a stream of liquefied slag-like material onto the concave upper face of a distributing rotor turning about a substantially vertical axis, tangentially discharging a layer of fine molten slag-like particles from the outer edge of the concave face portion of the distributing rotor in a horizontal plane, and concurrently directing outwardly converging annular blasts of pressurized steam onto the discharging layer of molten slag-like particles immediately adjacent the outer periphery of the distributing rotor to produce a turbulent mass of expanding steam and slag-likerparticles undergoing cooling and fiberizing.

3. A process for making mineral wool fibers from molten slag-like material which comprises pouring a stream of liquefied slag-like material onto the inner face of a cup-shaper distributing rotor turning about a substantially vertical axis, tangentially discharging a horizontal layer of fine molten slag-like particles from the outer edge of the distributing rotor, and concurrently directing annular blasts of pressurized steam radially outward with respect to the rotor from above and below the horizontal discharging layer of particles to converge on the layer immediately adjacent the outer edge of the cup-shaped rotor and to produce an annular mass of turbulent expanding steam and slag-like particles acting to break down and then fiberize the thus cooled particles.

4. A process for making mineral wool fibers from molten slag-like material which comprises heating a mass of slag-like material to approximately 3000 F. to liquefy said mass, pouring a stream of thus liquefied slag material onto the inner face of a cup-shaped portion of a distributing rotor rotating about a substantially vertical axis at a speed such as to tangentially disperse an annular layer of fine molten slag-like particles from the outer edge of the cup-shaped portion of rotor in a gen- .erally horizontal plane, and directing annular blasts of pressurized steam radially outward with respect to the rotor from above and below the horizontal annular layer of molten slag-like particles so as to converge on the layer of slag-like particles immediately adjacent the outer edge of the cup-shaped rotor portion, whereby to produce an annular turbulent mass of expanding steam that further breaks down the slag-like particles into smaller sizes, absorbs heat therefrom, and then fiberizes them.

5. Apparatus for making mineral wool fibers comprising a generally vertical wall forming a chamber, means for supplying molten slag-like material positioned immediately above the chamber, a rotary cup-shaped distributing member positioned within the chamber below the molten material source, said rotary distributing member being adapted to receive the molten material and disperse it in the form of a horizontal layer of fine molten particles, a pair of steam rings concentrically disposed with respect to the rotary distributing member above and below the annular particle layer for radially discharging converging annular blasts of steam onto said layer to fiberize the particles, means for displacing one ring with respect to the other to provide an increased space between confronting faces of the steam rings in order that unmelted particles of relatively large size may pass therebetween, a circular deflector extending around and spaced outwardly from the chamber wall and having a portion extending above the upper end of said wall, said deflector being adapted to deflect the unfiberized particles radially projected by the distributing member and drop them down outside the chamber wall.

6. Apparatus for making mineral wool fibers which comprises means for supplying molten slag-like material, a distributing rotor mounted for rotation about a vertical axis, said rotor having a cup-shaped upper portion with a smooth concave surface facing upwardly, means for directing a stream of molten slag-like material onto the concave surface of the rotor, means for rotating said 7 rotor to disperse the molten material in the form of a horizontal annular layer of fine molten particles, a pair of steam rings concentrically disposed with respect to the cup-shaped portion of the rotor, one steam ring being positioned above and one below the top of the cupshaped portion of the rotor, the confronting faces of the steam rings each having an annular opening sloping in a direction outward of the distributing rotor to discharge steam on the layer of fine molten particles further to disperse, cool, and fiberize the particles, and means for vertically displacing the upper ring with respect to the lower ring to provide an increased space between confronting faces of the steam rings in order that unmelted particles of relatively large size may pass therebetween.

References Cited in the file of this patent UNITED STATES PATENTS Fuller Oct. 26, Cofiin June 24, Kann Nov. 24, Harford et al. May 2, Rosengarth et al. Mar. 4, McClure May 4, Peyches Jan. 15, Slayter et al Sept. 9, Heymes et al. Jan. 13, Anliker May 10,

FOREIGN PATENTS Norway Oct. 26, 

